Dini's surface
Image:Mathematica dinis surface.png|thumb|350px|Dini's surface plotted with adjustable parameters by Wolfram Mathematica program
In geometry, Dini's surface is a surface with constant negative curvature that can be created by twisting a pseudosphere. It is named after Ulisse Dini and described by the following parametric equations:
Another description is a generalized helicoid constructed from the tractrix.